Printers are useful for producing printed images of a wide range of types. Printers print on receivers (or “imaging substrates” or “recording media”), such as pieces or sheets of paper or other planar media, glass, fabric, metal, or other objects. Examples of such media include fabrics, uncoated papers such as bond papers, semi-absorbent papers such as clay coated papers commonly used in lithographic printing (e.g., Potlatch Vintage Gloss, Potlatch Vintage Velvet, Warren Offset Enamel, and Kromekote papers), and non-absorbent papers such as polymer-coated papers used for photographic printing.
Printers typically operate using subtractive color: a substantially reflective recording medium is overcoated image-wise with cyan (C), magenta (M), yellow (Y), black (K), and other colorants. Various schemes can be used to print images. For example, inkjet printing deposits drops of liquid ink in appropriate locations on a recording medium to form an image. However, inkjet printing is limited in the density it can produce.
U.S. Pat. No. 4,943,816 to Sporer discloses the use of a marking fluid containing no dye so that a latent image in the form of fluid drops is formed on a piece of paper. The marking fluid is relatively non-wetting to the paper. Sporer teaches the use of a 300 dpi thermal inkjet printer to produce the latent image. Surface tension then causes colored powder to adhere to the fluid drops. Sporer teaches that only that portion of the droplet that has not penetrated or feathered into the paper is available for attracting dry ink, so this process is unsuitable for highly-absorbent papers such as newsprint. Because of the limitations taught by Sporer of using thermal drop-on-demand and the limitation of 300 dpi, this process is only suitable for low volume, low speed printing applications requiring only modest image quality. There is therefore a continuing need for a way of producing high-quality images at high speed using inkjet printers.